Where are clouds, stucci, wood textures in cycles materials?
Cycles is a completely different rendering engine, with its own system, separate settings, materials and different workflow. Blender internal materials and textures are not available under Cycles and the opposite is also true.

Cycles has it's own musgrave texture accessible through the node editor Add Menu > Textures > Musgrave. It has it's own set of settings and can be tweaked as just like Blender Internal.
You can even use other textures com combine, mix or deform the current one.